<html>
<head><meta charset="utf-8"><title>universe transition · wg-traits · Zulip Chat Archive</title></head>
<h2>Stream: <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/index.html">wg-traits</a></h2>
<h3>Topic: <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/universe.20transition.html">universe transition</a></h3>

<hr>

<base href="https://rust-lang.zulipchat.com">

<head><link href="https://rust-lang.github.io/zulip_archive/style.css" rel="stylesheet"></head>

<a name="135264806"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/universe%20transition/near/135264806" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/universe.20transition.html#135264806">(Oct 05 2018 at 16:23)</a>:</h4>
<p>So some of you may have seen that my PR <a href="https://github.com/rust-lang/rust/issues/54649" target="_blank" title="https://github.com/rust-lang/rust/issues/54649">#54649</a> landed — I'm now working on a follow-up that converts all of rustc to use <strong>universe-based constraints</strong> for higher-ranked stuff instead of the existing leak-check. This PR <em>was</em> basically working before I rebased, but now it doesn't, so I have to figure out what I did wrong. Hopefully will open it soon.</p>
<p>Even once it is <em>working</em>, we still have to do some crater runs and also improve the diagnostics, which are currently <strong>horrific</strong>.</p>



<a name="135272113"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/universe%20transition/near/135272113" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/universe.20transition.html#135272113">(Oct 05 2018 at 18:31)</a>:</h4>
<p><span class="user-mention" data-user-id="131694">@scalexm</span> for now, I opened a " second round of refactorings for universes <a href="https://github.com/rust-lang/rust/issues/54858" target="_blank" title="https://github.com/rust-lang/rust/issues/54858">#54858</a> " PR...</p>



<a name="135272266"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/universe%20transition/near/135272266" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> scalexm <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/universe.20transition.html#135272266">(Oct 05 2018 at 18:34)</a>:</h4>
<p><span class="user-mention" data-user-id="116009">@nikomatsakis</span> ok cool, will look soon</p>



<a name="135273699"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/universe%20transition/near/135273699" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/universe.20transition.html#135273699">(Oct 05 2018 at 18:57)</a>:</h4>
<p>debating whether to add a <em>few</em> more things in there...</p>



<a name="135424567"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/universe%20transition/near/135424567" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/universe.20transition.html#135424567">(Oct 08 2018 at 19:52)</a>:</h4>
<p>btw I've rebased my universes branch atop <a href="https://github.com/rust-lang/rust/pull/54858" target="_blank" title="https://github.com/rust-lang/rust/pull/54858">https://github.com/rust-lang/rust/pull/54858</a></p>



<a name="135424569"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/universe%20transition/near/135424569" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/universe.20transition.html#135424569">(Oct 08 2018 at 19:53)</a>:</h4>
<p>(which is now green)</p>



<a name="135424574"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/universe%20transition/near/135424574" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/universe.20transition.html#135424574">(Oct 08 2018 at 19:53)</a>:</h4>
<p>my universes branch is still failing some tests, I haven't had time to debug yet</p>



<a name="135424579"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/universe%20transition/near/135424579" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/universe.20transition.html#135424579">(Oct 08 2018 at 19:53)</a>:</h4>
<p>I'd like to land <a href="https://github.com/rust-lang/rust/pull/54858" target="_blank" title="https://github.com/rust-lang/rust/pull/54858">https://github.com/rust-lang/rust/pull/54858</a> first probably — then maybe I can pull a 3rd round of refactoring. ideally I can get the <em>actual</em> universe branch down to a relatively small PR before it lands, particularly since it'll need crater runs and things.</p>



<a name="135424729"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/universe%20transition/near/135424729" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> scalexm <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/universe.20transition.html#135424729">(Oct 08 2018 at 19:56)</a>:</h4>
<p><span class="user-mention" data-user-id="116009">@nikomatsakis</span> ok I've already read through it twice and it seems good to me</p>



<a name="135424767"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/universe%20transition/near/135424767" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> scalexm <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/universe.20transition.html#135424767">(Oct 08 2018 at 19:57)</a>:</h4>
<p>I'm ok with keeping "next universe" terminology</p>



<a name="135424802"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/universe%20transition/near/135424802" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/universe.20transition.html#135424802">(Oct 08 2018 at 19:58)</a>:</h4>
<p><span class="emoji emoji-1f44d" title="+1">:+1:</span> I think it's fine for now too</p>



<a name="135424810"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/universe%20transition/near/135424810" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/universe.20transition.html#135424810">(Oct 08 2018 at 19:58)</a>:</h4>
<p>I think the new terms <em>are</em> clearer though than "sub" or "super"</p>



<a name="135424813"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/universe%20transition/near/135424813" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/universe.20transition.html#135424813">(Oct 08 2018 at 19:58)</a>:</h4>
<p>in particular when I think things through in my head I tend to think in terms of "can name"</p>



<a name="135424817"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/universe%20transition/near/135424817" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/universe.20transition.html#135424817">(Oct 08 2018 at 19:58)</a>:</h4>
<p>(e.g., can this variable name that type...)</p>



<a name="135424826"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/universe%20transition/near/135424826" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> scalexm <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/universe.20transition.html#135424826">(Oct 08 2018 at 19:58)</a>:</h4>
<p>yes</p>



<a name="135424859"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/universe%20transition/near/135424859" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> scalexm <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/universe.20transition.html#135424859">(Oct 08 2018 at 19:59)</a>:</h4>
<p>so, can we merge it?</p>



<a name="135424871"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/universe%20transition/near/135424871" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/universe.20transition.html#135424871">(Oct 08 2018 at 19:59)</a>:</h4>
<p>I think so</p>



<a name="135424933"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/universe%20transition/near/135424933" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/universe.20transition.html#135424933">(Oct 08 2018 at 20:00)</a>:</h4>
<p>then I can get to the next refactorings PR :)</p>



<a name="135428379"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/universe%20transition/near/135428379" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/universe.20transition.html#135428379">(Oct 08 2018 at 21:15)</a>:</h4>
<p>ok, I found the bug in my rebase. It wasn't in my PR, it was an interaction with <a href="https://github.com/rust-lang/rust/pull/54624" target="_blank" title="https://github.com/rust-lang/rust/pull/54624">https://github.com/rust-lang/rust/pull/54624</a>, which was leaning on the <code>leak_check</code> in ways that I did not fully understand</p>



<a name="135428666"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/universe%20transition/near/135428666" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/universe.20transition.html#135428666">(Oct 08 2018 at 21:21)</a>:</h4>
<p>ok, well, sort of, I still get some failing tests...</p>



<a name="135428692"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/universe%20transition/near/135428692" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/universe.20transition.html#135428692">(Oct 08 2018 at 21:21)</a>:</h4>
<p>(but related to that same issue)</p>



<a name="135830082"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/universe%20transition/near/135830082" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/universe.20transition.html#135830082">(Oct 15 2018 at 13:20)</a>:</h4>
<p><strong>Status update:</strong> </p>
<ul>
<li>Waiting on <a href="https://github.com/rust-lang/rust/pull/54858" target="_blank" title="https://github.com/rust-lang/rust/pull/54858">https://github.com/rust-lang/rust/pull/54858</a> to land, first of all (rebased, though).</li>
<li>Got a bit stalled because of the leak-check interactions with <a href="https://github.com/rust-lang/rust/issues/54624" target="_blank" title="https://github.com/rust-lang/rust/issues/54624">#54624</a>. I am leaning towards resurrecting my alternate approach from <a href="https://github.com/rust-lang/rust/issues/54401" target="_blank" title="https://github.com/rust-lang/rust/issues/54401">#54401</a>, but even that requires a <em>bit</em> of work -- in particular, I need to add a variant of <code>probe</code> that indicates whether region constraints were added during the <code>probe</code>. I may tackle that this morning. I'd like to get the PR opened up, though I'd also like to see if I can carve out another "refactoring PR" before landing it, I feel like it's still more code in one PR that I'd like.</li>
</ul>



<a name="135858291"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/universe%20transition/near/135858291" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/universe.20transition.html#135858291">(Oct 15 2018 at 21:03)</a>:</h4>
<p>woohoo, <a href="https://github.com/rust-lang/rust/pull/54858" target="_blank" title="https://github.com/rust-lang/rust/pull/54858">https://github.com/rust-lang/rust/pull/54858</a> landed</p>



<a name="135897879"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/universe%20transition/near/135897879" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/universe.20transition.html#135897879">(Oct 16 2018 at 12:55)</a>:</h4>
<p>OK, I rebased atop master, and I got around to fixing the leak-check interactions, and the universes branch now builds and passes tests! (Modulo that a lot of the diagnostics are terrible now and of course that coherence currently changes behavior)</p>



<a name="135897886"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/universe%20transition/near/135897886" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/universe.20transition.html#135897886">(Oct 16 2018 at 12:55)</a>:</h4>
<p>I'll try to cleanup the PR a bit and think about how to take next steps towards landing</p>



<a name="135897894"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/universe%20transition/near/135897894" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/universe.20transition.html#135897894">(Oct 16 2018 at 12:55)</a>:</h4>
<p>though one thing I'd probably like to start with is to do a crater run</p>



<a name="136398794"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/universe%20transition/near/136398794" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/universe.20transition.html#136398794">(Oct 24 2018 at 10:01)</a>:</h4>
<p><span class="user-mention" data-user-id="131694">@scalexm</span> opened <a href="https://github.com/rust-lang/rust/pull/55305" target="_blank" title="https://github.com/rust-lang/rust/pull/55305">https://github.com/rust-lang/rust/pull/55305</a> — a 3rd refactoring PR</p>



<a name="136479500"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/universe%20transition/near/136479500" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jake Goulding <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/universe.20transition.html#136479500">(Oct 25 2018 at 14:11)</a>:</h4>
<p>The motto of this work:</p>
<blockquote>
<p>If you wish to make an apple pie from scratch, you must first invent the universe.</p>
</blockquote>



<a name="136493718"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/universe%20transition/near/136493718" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/universe.20transition.html#136493718">(Oct 25 2018 at 17:32)</a>:</h4>
<p>Argh. I am looking at my final branch and I noticed it's missing what I believe to be some crucial logic, such that something like <code>exists&lt;'a&gt; for&lt;'b&gt; { 'a = 'b }</code> would be (incorrectly) accepted — but I can't come up with a Rust test case that exposes it yet. :)</p>



<a name="136493725"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/universe%20transition/near/136493725" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/universe.20transition.html#136493725">(Oct 25 2018 at 17:32)</a>:</h4>
<p>these are the times I wish for more "unit-testability"</p>



<a name="136493735"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/universe%20transition/near/136493735" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/universe.20transition.html#136493735">(Oct 25 2018 at 17:33)</a>:</h4>
<p>although it's really better to wind up with end-to-end tests I think</p>



<a name="136507035"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/universe%20transition/near/136507035" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/universe.20transition.html#136507035">(Oct 25 2018 at 21:05)</a>:</h4>
<p>ok, managed a test</p>



<a name="136807881"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/universe%20transition/near/136807881" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/universe.20transition.html#136807881">(Oct 30 2018 at 21:19)</a>:</h4>
<p>Posted <a href="https://github.com/rust-lang/rust/pull/55517" target="_blank" title="https://github.com/rust-lang/rust/pull/55517">https://github.com/rust-lang/rust/pull/55517</a></p>



<a name="136876132"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/universe%20transition/near/136876132" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> scalexm <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/universe.20transition.html#136876132">(Oct 31 2018 at 19:45)</a>:</h4>
<p><span class="user-mention" data-user-id="116009">@nikomatsakis</span> omg it seems like your universes refactor 3 is never going to land</p>



<a name="136878519"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/universe%20transition/near/136878519" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/universe.20transition.html#136878519">(Oct 31 2018 at 20:21)</a>:</h4>
<p>lol yes</p>



<a name="136878524"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/universe%20transition/near/136878524" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/universe.20transition.html#136878524">(Oct 31 2018 at 20:21)</a>:</h4>
<p>it's always hovering 3-5 things down :)</p>



<a name="136926644"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/universe%20transition/near/136926644" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> scalexm <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/universe.20transition.html#136926644">(Nov 01 2018 at 14:56)</a>:</h4>
<p><span class="user-mention" data-user-id="116009">@nikomatsakis</span> time to do a crater run on your universes PR?</p>



<a name="136927539"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/universe%20transition/near/136927539" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> scalexm <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/universe.20transition.html#136927539">(Nov 01 2018 at 15:10)</a>:</h4>
<p>btw I've read through it, it seems to me that the critical new code is just a few lines in <code>src/librustc/infer/lexical_region_resolve/mod.rs</code> right?</p>



<a name="136927562"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/universe%20transition/near/136927562" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> scalexm <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/universe.20transition.html#136927562">(Nov 01 2018 at 15:10)</a>:</h4>
<p>but maybe I'm overlooking something</p>



<a name="136931749"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/universe%20transition/near/136931749" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/universe.20transition.html#136931749">(Nov 01 2018 at 16:12)</a>:</h4>
<p>yep, it's not a lot of code</p>



<a name="136931759"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/universe%20transition/near/136931759" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/universe.20transition.html#136931759">(Nov 01 2018 at 16:12)</a>:</h4>
<p>it probably is ready for a crater run, yes</p>



<a name="136931771"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/universe%20transition/near/136931771" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/universe.20transition.html#136931771">(Nov 01 2018 at 16:12)</a>:</h4>
<p>I'll do a try build</p>



<a name="136942291"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/universe%20transition/near/136942291" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/universe.20transition.html#136942291">(Nov 01 2018 at 18:54)</a>:</h4>
<p>ok, <a href="https://github.com/rust-lang/rust/pull/55517#issuecomment-435147309" target="_blank" title="https://github.com/rust-lang/rust/pull/55517#issuecomment-435147309">starting a crater run</a></p>
<p>(&lt;3 <span class="user-mention" data-user-id="121055">@Pietro Albini</span> &lt;3)</p>



<a name="146869305"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/universe%20transition/near/146869305" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/universe.20transition.html#146869305">(Nov 06 2018 at 14:50)</a>:</h4>
<p><span class="user-mention" data-user-id="131694">@scalexm</span> did you see that the crater run seemed to come out clean? Exciting</p>



<a name="146869344"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/universe%20transition/near/146869344" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> scalexm <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/universe.20transition.html#146869344">(Nov 06 2018 at 14:51)</a>:</h4>
<p><span class="user-mention" data-user-id="116009">@nikomatsakis</span> yes I did! Time to fix the diagnostics now lol</p>



<a name="146869758"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/universe%20transition/near/146869758" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/universe.20transition.html#146869758">(Nov 06 2018 at 14:58)</a>:</h4>
<p>yeah, I was debating about whether to try and improve them -- I might be able to reproduce the existing ones instead</p>



<a name="146869764"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/universe%20transition/near/146869764" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/universe.20transition.html#146869764">(Nov 06 2018 at 14:58)</a>:</h4>
<p>I'd rathre "do better" but it'd be ok to leave that</p>



<a name="147980404"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/universe%20transition/near/147980404" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/universe.20transition.html#147980404">(Nov 19 2018 at 17:19)</a>:</h4>
<p><span class="user-mention" data-user-id="131694">@scalexm</span> so I've improved the errors on <a href="https://github.com/rust-lang/rust/pull/55517" target="_blank" title="https://github.com/rust-lang/rust/pull/55517">https://github.com/rust-lang/rust/pull/55517</a> -- at least to some extent</p>



<a name="147980415"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/universe%20transition/near/147980415" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/universe.20transition.html#147980415">(Nov 19 2018 at 17:19)</a>:</h4>
<p>any objections to r=scalexm? :) (I think you read it over, correct?)</p>



<a name="148402285"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/universe%20transition/near/148402285" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/universe.20transition.html#148402285">(Nov 26 2018 at 22:12)</a>:</h4>
<p>ugh</p>



<a name="148402290"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/universe%20transition/near/148402290" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/universe.20transition.html#148402290">(Nov 26 2018 at 22:12)</a>:</h4>
<p>apparently <a href="http://probe.rs" target="_blank" title="http://probe.rs">probe.rs</a> (and maybe other code) is introduced <code>'erased</code> lifetimes</p>



<a name="148402291"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/universe%20transition/near/148402291" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/universe.20transition.html#148402291">(Nov 26 2018 at 22:12)</a>:</h4>
<p>/me investigates</p>



<a name="154205357"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/universe%20transition/near/154205357" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/universe.20transition.html#154205357">(Jan 02 2019 at 22:17)</a>:</h4>
<p>finally getting around to rebasing this. what a pain.</p>



<hr><p>Last updated: Aug 07 2021 at 22:04 UTC</p>
</html>